Bearing members of this type are suitably used as bearing members that form a bearing surface with a deposited surface of their electroformed part, utilizing the fact that the surface deposited on the surface of a master, or the molding matrix of this electroformed part, can be formed with high precision after the surface accuracy of the master surface.
For example, Japanese Patent Application Laid-Open No. 2003-56552 (Patent Document 1) has disclosed a bearing member which has an electroformed part integrally die formed as an insert, and a bearing unit which includes the same. This bearing member is formed by: forming an cylindrical electroformed part, or electroforming shell, by deposition on a master shaft, or a molding matrix of the electroformed part, at an area other than a nonconductive masked portion; die forming the bearing member of resin with this electroformed part as an insert; and then separating the electroformed part of the bearing member from the master shaft, so that the inner periphery of the electroformed part, the separation surface, can be directly used as a bearing surface. According to this bearing member, the inner periphery of the electroformed part or electroforming shell forms the shaft hole of the bearing member, with a high roundness, a high dimensional accuracy of the inner diameter, and favorable slidability. The clearance to a shaft member to be inserted into the shaft hole can be minimized for precise rotation, sliding, or sliding rotation.
Moreover, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-246223 (Patent Document 2), ones having a bearing member made of resin for the sake of reduced material cost and machining cost have been known recently.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-56552.    [Patent Document 2] Japanese Patent Application Laid-Open No. Hei 10-246223.